CONTENT DELIVERY SYSTEM, CACHE SERVER, AND CONTENT DELIVERY METHOD

• US 20140344392A1
• Filed: 09/21/2012
• Published: 11/20/2014
• Est. Priority Date: 09/21/2011
• Status: Abandoned Application

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ozawa, Kazunori
• Application Number:
  US14/345,435
• Publication Number:
  US 20140344392A1
• Time in Patent Office: Days
• US Class Current: 709/213
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/288 Distributed intermediate devices, i.e. intermediate devices for interaction with other intermediate devices on the same level
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04N 21/23106 involving caching operations prefetching while addressing of a memory level in which the access to the desired data or data block requires associative addressing means within memory systems or architectures G06F12/0862; caching at an intermediate stage in a data network H04L67/568
• CPC Class Codes: H04N 21/234381 by altering the temporal resolution, e.g. decreasing the frame rate by frame skipping
• CPC Class Codes: H04N 21/6131 involving transmission via a mobile phone network wireless downlink channel access H04W74/006
• CPC Class Codes: H04N 21/64738 Monitoring network characteristics, e.g. bandwidth, congestion level data switched network analysis H04L41/14; monitoring functioning in data switched networks H04L43/0817; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/64784 Data processing by the network data processing in packet switching systems H04L12/56; flow control in packet networks H04L47/10; intermediate storage or scheduling H04L49/90; provisioning of proxy services in data packet switching networks H04L67/56

Abstract

A cache server includes an accumulation unit that accumulates a content(s) stored in a delivery server apparatus. The cache server, by using information included in a request message from a mobile terminal, determines which one of the cache servers arranged on a mobile network accumulates a content requested by the mobile terminal. The cache server reads a file corresponding to the requested content from the determined cache server and outputs the file to the accumulation unit. In addition, the cache server estimates a bandwidth of the mobile network based on a signal from the mobile terminal, reads the file corresponding to the requested content from the accumulation unit, and extracts a stream from the file. The cache server generates a stream by deleting at least part of frames from the stream so that a bit rate of the generated stream does not exceed the band. The cache server stores the generated stream in a packet and transmits the packet to the mobile terminal.

Claims

1. A content delivery system, comprising:

a plurality of cache servers on a mobile network;

wherein each of the plurality of cache servers comprises;

a temporary content accumulation unit that temporarily accumulates at least part of contents stored in a delivery server apparatus delivering a content(s) on the Internet;

a determination unit that by using information included in a content request message from a mobile terminal determines which one of the plurality of cache servers accumulates a content requested by the mobile terminal;

a content acquisition unit that reads a file corresponding to the requested content from the determined cache server and outputs the file to the temporary content accumulation unit; and

a delivery unit that estimates a bandwidth of the mobile network based on a predetermined signal from the mobile terminal, reads the file corresponding to the requested content from the temporary content accumulation unit, extracts a stream from the file, generates a stream by deleting at least part of frames from the stream so that a bit rate of the generated stream does not exceed the bandwidth, stores the generated stream in a packet, and transmits the packet to the mobile terminal;

wherein, if the delivery unit receives a response packet from the mobile terminal in response to a transmitted packet transmitted to the mobile terminal, the delivery unit estimates the bandwidth of the mobile network based on a difference between a transmission time of the transmitted packet and a reception time of the response packet and based on a size of the transmitted packet.

2. The content delivery system according to claim 1;

wherein the delivery unit reads the file corresponding to the requested content from the temporary content accumulation unit in portions, extracts a stream from the file divided in portions, and generates a stream by deleting at least one frame whose priority is relatively low from the stream so that a bit rate of the generated stream does not exceed the bandwidth.

4. The content delivery system according to claim 1;

wherein, if the delivery unit receives a signal indicating a congestion state of the mobile network from the mobile terminal, the delivery unit does not transmit the packet for a predetermined period.

5. The content delivery system according to claim 1;

wherein the delivery unit estimates the bandwidth of the mobile network based on a predetermined signal from the mobile terminal, reads the file corresponding to the requested content from the temporary content accumulation unit, extracts a stream from the file, generates a stream by deleting at least part of frames from the stream so that a bit rate of the generated stream does not exceed the bandwidth, stores the stream in a file, transmits a packet including the file storing the adjusted stream to the mobile terminal while controlling transmission timing based on a buffer capacity of the mobile terminal at least for a certain period.

6. The content delivery system according to claim 5;

wherein, if a bit rate of the file storing the adjusted stream is lower than the bandwidth, the delivery unit calculates a period that is required for a buffer amount of the mobile terminal to reach the buffer capacity based on the bit rate and the buffer capacity and does not transmit the packet during a period until the buffer amount reaches zero, which period is determined based on the calculated period.

7. The content delivery system according to claim 5;

wherein, if a bit rate of the file storing the adjusted stream is equal to the bandwidth, the delivery unit calculates a period required for a buffer amount of the mobile terminal to reach zero based on a bit rate at which the mobile terminal reproduces a content and on the buffer capacity and does not transmit the packet for the period.

8. The content delivery system according to claim 5;

wherein the delivery unit reads the file corresponding to the requested content from the temporary content accumulation unit in portions, extract a stream from the file divided in portions, and generates a stream by deleting at least one frame whose priority is relatively low from the stream so that a bit rate of the generated stream does not exceed the bandwidth.

9. The content delivery system according to claim 5;

wherein, if the delivery unit receives a response packet from the mobile terminal in response to a transmitted packet transmitted to the mobile terminal, the delivery unit estimates the bandwidth of the mobile network based on a difference between a transmission time of the transmitted packet and a reception time of the response packet and based on a size of the transmitted packet.

10. The content delivery system according to claim 5;

wherein, if the delivery unit receives a signal indicating a congestion state of the mobile network from the mobile terminal, the delivery unit does not transmit the packet for a predetermined period.

11. The content delivery system according to claim 1;

wherein the plurality of cache servers are transparent or fully transparent proxy servers.

12. The content delivery system according to claim 1;

wherein the mobile network is a 3G (3rd Generation) mobile network or an LTE (Long Term Evolution)/EPC (Evolved Packet Core) network.

3. (canceled)

13. A cache server, comprising:

a temporary content accumulation unit that temporarily accumulates at least part of contents stored in a delivery server apparatus delivering a content(s) on the Internet;

a determination unit that by using information included in a content request message from a mobile terminal determines which one of the plurality of cache servers on a mobile network accumulates a content requested by the mobile terminal;

a content acquisition unit that reads a file corresponding to the requested content from the determined cache server and outputs the file to the temporary content accumulation unit; and

a delivery unit that estimates a bandwidth of the mobile network based on a predetermined signal from the mobile terminal, reads the file corresponding to the requested content from the temporary content accumulation unit, extracts a stream from the file, generates a stream by deleting at least part of frames from the stream so that a bit rate of the generated stream does not exceed the bandwidth, stores the generated stream in a packet, and transmits the packet to the mobile terminal;

wherein, if the delivery unit receives a response packet from the mobile terminal in response to a transmitted packet transmitted to the mobile terminal, the delivery unit estimates the bandwidth of the mobile network based on a difference between a transmission time of the transmitted packet and a reception time of the response packet and based on a size of the transmitted packet.

14. The cache server according to claim 13;

wherein the delivery unit reads the file corresponding to the requested content from the temporary content accumulation unit in portions, extracts a stream from the file divided in portions, and generates a stream by deleting at least one frame whose priority is relatively low from the stream so that a bit rate of the generated stream does not exceed the bandwidth.

16. The cache server according to claim 13;

wherein, if the delivery unit receives a signal indicating a congestion state of the mobile network from the mobile terminal, the delivery unit does not transmit the packet for a predetermined period.

17. The cache server according to claim 13;

wherein the delivery unit estimates the bandwidth of the mobile network based on a predetermined signal from the mobile terminal, reads the file corresponding to the requested content from the temporary content accumulation unit, extracts a stream from the file, generates a stream by deleting at least part of frames from the stream so that a bit rate of the generated stream does not exceed the bandwidth, stores the stream in a file, and transmits a packet including the file storing the adjusted stream to the mobile terminal while controlling transmission timing based on a buffer capacity of the mobile terminal at least for a certain period.

18. The cache server according to claim 17;

wherein, if a bit rate of the file storing the adjusted stream is lower than the bandwidth, the delivery unit calculates a period that is required for a buffer amount of the mobile terminal to reach the buffer capacity based on the bit rate and the buffer capacity and does not transmit the packet during a period until the buffer amount reaches zero, which period is determined based on the calculated period.

19. The cache server according to claim 17;

wherein, if a bit rate of the file storing the adjusted stream is equal to the bandwidth, the delivery unit calculates a period required for a buffer amount of the mobile terminal to reach zero based on a bit rate at which the mobile terminal reproduces a content and on the buffer capacity and does not transmit the packet for the period.

20. The cache server according to claim 17;

wherein the delivery unit reads the file corresponding to the requested content from the temporary content accumulation unit in portions, extracts a stream from the file divided in portions, and generates a stream by deleting at least one frame whose priority is relatively low from the stream so that a bit rate of the generated stream does not exceed the bandwidth.

21. The cache server according to claim 17;

wherein, if the delivery unit receives a response packet from the mobile terminal in response to a transmitted packet transmitted to the mobile terminal, the delivery unit estimates the bandwidth of the mobile network based on a difference between a transmission time of the transmitted packet and a reception time of the response packet and based on a size of the transmitted packet.

15. (canceled)

22. (canceled)

23. A content delivery method, comprising:

by a cache server, temporarily accumulating at least part of contents stored in a delivery server apparatus delivering a content(s) on the Internet in a temporary content accumulation unit provided with the cache server;

by using information included in a content request message from a mobile terminal, determining which one of the plurality of cache servers on a mobile network accumulates a content requested by the mobile terminal;

reading a file corresponding to the requested content from the determined cache server and outputting the file to the temporary content accumulation unit;

estimating a bandwidth of the mobile network based on a predetermined signal from the mobile terminal;

reading the file corresponding to the requested content from the temporary content accumulation unit; and

extracting a stream from the read file, generating a stream by deleting at least part of frames from the stream so that a bit rate of the generated stream does not exceed the bandwidth, storing the generated stream in a packet, and transmitting the packet to the mobile terminal;

wherein, if the cache server receives a response packet from the mobile terminal in response to a transmitted packet transmitted to the mobile terminal, the cache server estimates the bandwidth of the mobile network based on a difference between a transmission time of the transmitted packet and a reception time of the response packet and based on a size of the transmitted packet.

24-32. -32. (canceled)